Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study
Ferrous oxalate dihydrate (α-FOD) was synthesized from Ecuadorian black sands for phenol removal from aqueous solutions. Visible light-driven photodegradation kinetics were studied by varying the initial pollutant concentration, solution pH, and α-FOD dosage and by adding peroxydisulfate (PDS), incl...
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MDPI AG
2025-05-01
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| author | Salomé Galeas Víctor H. Guerrero Patricia I. Pontón Vincent Goetz |
| author_facet | Salomé Galeas Víctor H. Guerrero Patricia I. Pontón Vincent Goetz |
| author_sort | Salomé Galeas |
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| description | Ferrous oxalate dihydrate (α-FOD) was synthesized from Ecuadorian black sands for phenol removal from aqueous solutions. Visible light-driven photodegradation kinetics were studied by varying the initial pollutant concentration, solution pH, and α-FOD dosage and by adding peroxydisulfate (PDS), including quenching tests. A representative model of phenol photodegradation was obtained by the Langmuir–Hinshelwood mechanism over a large range of concentrations (apparent kinetic constant, k = 0.524 h<sup>−1</sup>). Almost complete removal was reached within 1 h under dark + 9 h under visible irradiation. The degradation rate was slightly affected by pH in the range of 3 to 9, with a significant improvement at pH 11 (k = 1.41-fold higher). The optimal α-FOD dosage was ~0.5 g/L. Two regimes were observed when using PDS: first, a heterogeneous Fenton-like process during the first few minutes after PDS addition; second, pure photocatalysis to completely remove the phenol. When comparing the two systems, without and with PDS, the half-life time for pure photocatalysis was 2.5 h (after the lamp was switched on). When adding PDS (1.0 mM), the half-life time was reduced to a few minutes (5 min after PDS addition, phenol removal was 66%). The photocatalyst presented remarkable degradation efficiency up to five repeated cycles. |
| format | Article |
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| language | English |
| publishDate | 2025-05-01 |
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| spelling | doaj-art-530fc79f5226447fb0b5ecc786db9ac22025-08-20T01:49:14ZengMDPI AGMolecules1420-30492025-05-01309205910.3390/molecules30092059Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics StudySalomé Galeas0Víctor H. Guerrero1Patricia I. Pontón2Vincent Goetz3Doctoral School Energy and Environment, University of Perpignan Via Domitia (UPVD), 52 Avenue Paul Alduy, 66100 Perpignan, FranceDepartment of Materials, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito 170525, EcuadorDepartment of Materials, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito 170525, EcuadorPROMES-CNRS UPR 8521, PROcesses Materials and Solar Energy, Rambla de la Thermodynamique, 66100 Perpignan, FranceFerrous oxalate dihydrate (α-FOD) was synthesized from Ecuadorian black sands for phenol removal from aqueous solutions. Visible light-driven photodegradation kinetics were studied by varying the initial pollutant concentration, solution pH, and α-FOD dosage and by adding peroxydisulfate (PDS), including quenching tests. A representative model of phenol photodegradation was obtained by the Langmuir–Hinshelwood mechanism over a large range of concentrations (apparent kinetic constant, k = 0.524 h<sup>−1</sup>). Almost complete removal was reached within 1 h under dark + 9 h under visible irradiation. The degradation rate was slightly affected by pH in the range of 3 to 9, with a significant improvement at pH 11 (k = 1.41-fold higher). The optimal α-FOD dosage was ~0.5 g/L. Two regimes were observed when using PDS: first, a heterogeneous Fenton-like process during the first few minutes after PDS addition; second, pure photocatalysis to completely remove the phenol. When comparing the two systems, without and with PDS, the half-life time for pure photocatalysis was 2.5 h (after the lamp was switched on). When adding PDS (1.0 mM), the half-life time was reduced to a few minutes (5 min after PDS addition, phenol removal was 66%). The photocatalyst presented remarkable degradation efficiency up to five repeated cycles.https://www.mdpi.com/1420-3049/30/9/2059α-FODlow-cost precursorFenton likeheterogeneous photocatalysisorganic micropollutants |
| spellingShingle | Salomé Galeas Víctor H. Guerrero Patricia I. Pontón Vincent Goetz Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study Molecules α-FOD low-cost precursor Fenton like heterogeneous photocatalysis organic micropollutants |
| title | Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study |
| title_full | Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study |
| title_fullStr | Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study |
| title_full_unstemmed | Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study |
| title_short | Visible Light-Driven Phenol Degradation via Advanced Oxidation Processes with Ferrous Oxalate Obtained from Black Sands: A Kinetics Study |
| title_sort | visible light driven phenol degradation via advanced oxidation processes with ferrous oxalate obtained from black sands a kinetics study |
| topic | α-FOD low-cost precursor Fenton like heterogeneous photocatalysis organic micropollutants |
| url | https://www.mdpi.com/1420-3049/30/9/2059 |
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